1. Field of the Invention
The present invention relates generally to door locks of the type used on large doors of moving vans and the like, and, more particularly, to a door lock including a lockable recessed handle.
2. Prior Art
Door locks of the type including an elongate shaft pivotally supported on a pivoted door and carrying cam members on opposite end regions of the shaft for releasably engaging keeper members carried on opposite sides of a door frame to retain the door in a closed position, are well known. Locks of this type are typically provided with a handle connected to the shaft for rotating the shaft to bring the cam members into and out of engagement with the keeper members. Such locks are commonly used on semi-trailer truck doors and the like.
Locks of the type described having a pan-shaped housing in which the handle is nested when the lock is locked, are also well known. Such locks are frequently used on the side doors of moving vans and the like where it is desired that the handle not project beyond the outer surface of the door when the door is locked. One such lock is sold by Eberhard Manufacturing Company Cleveland, Oh. 44136, under the model designation 5661.
It is known to provide the handles of locks such as Eberhard model 5661 with a key-operated lock cylinder to retain the operating handle in a locked position. A drawback of proposals for providing a key-operated cylinder in such a lock is that components of the resulting assembly can be bent, broken, or otherwise damaged by the application of undue force, as during tampering, whereby the locking action of the assembly is readily overcome. Moreover, previous proposals in no way provide a back-up or secondary locking system which will operate to maintain the lock locked even if the locking action of the primary locking system has been overcome.
It is also known to provide the handles of locks such as Eberhard model 5661 with a handle return spring interposed between the pan-shaped housing and the handle itself. A drawback of previous proposals has been that the spring rubs against the handle and causes the protective, corrosion resistant finish applied to the handle to be worn away quite rapidly.